Because I think sharing music is one of the greatest things, here is my list of favorite songs for Autumn. (This includes Halloween songs as well.)
Golden Leaves by Passenger [link] for a sweet, sad bit of reflection.
Moon Trance by Lindsey Stirling, [link] a personal favorite of mine (as long as you ignore the somewhat sub-par acting ) if you want something boppy and energetic.
California Dreamin' by the Beach Boys [link] for when the cold weather gets you down. (I know it's technically for winter, but it could also apply to fall!)
Thriller by Michael Jackson [link] -- a classic!
Hotel California by the Eagles. [link] Maybe not a typical autumn song, but there sure is some kind of creepy feel to it.
The Coraline Soundtrack [link] for a creepy and dream-like feel.
Reefer Madness soundtrack [link] for something spooky and fun
The Walking Dead theme song [link] (or soundtrack) for that itching, nervous feeling.
Also this one: [link]
The Nightmare before Christmas Soundtrack [link](Obviously.)
I also heard there's a playlist of the same songs done by other music artists, but I haven't discovered it yet. :/
And on that note:
This is Aperture,[link] The Wheatley Song [link] and Making Science [link] by Harry Callaghan for a Portal 2 twist on Danny Elfman's music.
And if I think of more, I'll add them!